battery ?

yeah, batterys are 14.7 volts

a battery with a dead cell is not going to provide enough cranking amps to energize the cranking mechanism.

a 60 dollar battery from sears works well.

mho vfe

Now, that's news to me, presume the starter turned over, it may be be a wipe-out of the comp.? That's unusual.

I don't know what you mean about the computer. Max charge is 12.6 volts. It is a Pb-PbSO4 reaction. A dead cell often is not really dead voltage wise. It is at

2.1 volts but has very little amperage under load. What was the battery voltage when the headlights were on?

Computer must see a minimum cranking voltage or nothing happens. Defective batteries do bad things to the PCM and its subsystems

Since it didn't start when you jumped it, I have to wonder if perhaps the battery cables were crudded up. Maybe the dealer didn't clean the cables before running a battery test?

Ted

Come to think of it, it might have been poor battery cable-connects, not sending enough voltage to the comp. to keep it "alive".

i still thought the starter pak should have supplied enough power to at least see a spark at the plug when i tested that? either way i wonder if it wasn't the battery all along then and not the $400.00 other parts they replaced? thanks for the replies

when a starter is continually subjected to an overload repeatedly, or from excessive use,

it has a tendency to "smoke". when this happens heavy bumps on the housing

sometimes makes for a temporary reconnect, and/or conduction enough to - start, maybe.

mho vfe

Yes I have a thought - How can anyone answer a question like that?

The statement "we got no spark, even if i jumped it with a portable power pack" implies that the starter was cranking the engine normally both with and without a jump. So the question sounds like you are asking

->

Is it possible for the battery (and/or battery plus jump) to deliver enough power to crank the engine normally but somehow the computer would detect a defect in the battery and refuse to function? The above analysis assumes that if the engine was not cranking normally that detail would have been mentioned in the question. For instance if you couldn't get the engine to crank at all getting no spark would be pretty normal. But if one starts assuming that you left out a critical detail like the engine wouldn't crank then one might also wonder what else important was omitted. So for all I know the car wouldn't start because it was out of gas 8^}

-jim

yes this is what i really wanted to know that if it's a battery with a dead cell but still turned over some and then we applied a jump to it , and it turned over fine,we still got no spark at the plugs? how come?

Is it possible for the battery (and/or battery plus jump) to deliver enough power to crank the engine normally but somehow the computer would detect a defect in the battery and refuse to function?

No idea. My point was if you want an answer that means anything - you need to supply facts in detail. Prom what I can gather the car had some sort of problem which required some kind of work that cost $400 and then under some unknown circumstance it wouldn't start and then you jumped it and it still wouldn't start and then the dealer put in a battery for $118 and after that no problems. And your question is -> Was the battery maybe the only thing wrong all along?

-jim

Yes, for sure. Jeeps made by Chrysler are very prone to that. The starter loads the battery down and the voltage drops lower than the computer needs to turn on.

It is especially bad in the rust belt where ground straps and connections get corroded.... Lots of folks forget that cables have 2 ends also.....

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail >